build: Add multi-architecture docker image push

.github/workflows/cd.yml

@@ -12,10 +12,45 @@ jobs:
 
     # Only runs if CI was successful
     if: ${{ github.event.workflow_run.conclusion == 'success' }}  
+    strategy:
+      matrix:
+        platform: [linux/amd64, linux/arm64]
+
     steps:
-      - uses: actions/checkout@v4
-      - name: Build the Docker image
-        run: docker build . --file Dockerfile --tag ntnu-kpro-ai-assistant:$(date +%s)
+      # Checkout the repository
+      - name: Checkout code
+        uses: actions/checkout@v3
 
-      - name: Push the Docker image
-        run: echo TODO Push the Docker image
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Cache Docker layers
+        uses: actions/cache@v3
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }} 
+
+      - name: Build and Push Docker image
+        run: |
+          docker buildx build \
+            --cache-from=type=local,src=/tmp/.buildx-cache \
+            --cache-to=type=local,dest=/tmp/.buildx-cache-new \
+            --platform ${{ matrix.platform }} \
+            -t ghcr.io/kartAI/ntnu-kpro-ai-assistant:${{ github.sha }} \
+            -t ghcr.io/kartAI/ntnu-kpro-ai-assistant:latest \
+            --push .
+
+      - name: Clean up
+        run: docker builder prune -f